Question

1. explain (include a labeled diagram )kirchhoffs loop rule.

2.explain (include a labeled diagram )kirchhoffs junction rule .

3.using kirchhoffs laws prove the following equation.

R(equ) =R1+R2+R3+.....

Answer 1

1) Kirchhoffs loop rule : The algabraic sum of emfs or potential differences around a closed circuit is zero.

This shows that electrostatic force is a conservative force.

For the application of Kirchhof's laws following sign convention are to be considered;

The change in potential in traveling a resistance in the direction of current is -iR while in the opposite direction is +iR

The change in potential in traversing an emf source from negative to positive terminal is +E while in the opposite direction is -E irrespective of the direction of current in the circuit.

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2) Kirchhoffs junction rule : The algebraic sum of electric currents at a junction is zero.

While applying this rule, take currents approaching the junction as +ve and those leaving it as -ve.

For the junction P

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3) For our simplicity let us take only 3 resistors in the circuit and derive for equivalent reistance.

In this way it can be derived for n resistors connected in series.